Download 5.1 Ratio and Proportion Learning Objectives: 1. Write ratios as

5.1 Ratio and Proportion Learning Objectives: 1. Write ratios as fractions. 2. Write rates as fractions and find unit rates. 3. Determine whether proportions are true. 4. Find an unknown number in a proportion. 5. Solve problems by writing proportions. 6. Key Vocabulary: ratio, rate, unit rate, proportion, cross product. A. Ratios Ratio—is the quotient of two quantities. Three ways to write a ratio: a
1. a to b 2. 3. a : b b
Example 1. Write each ratio as a fraction in simplest form. 1. 20 to 30 2. 6.6 miles to 10 miles B. Writing Rates as Fractions Rates are used to compare different kinds of quantities. Example 2. Write each rate as a fraction in simplest form: 6 tests for 30 students C. Proportions Proportion—is a statement that two ratios or rates are equal. Using Cross Products Rule to Determine Whether Proportions Are True or False Example 4. Determine whether each proportion is true or false. 3 4
= 1. 6 8
2
8
8
9 = 9 7
30
2
2. D. Finding Unknown Numbers in Proportions Example 5. Solve the proportion. 8 4
= 1. x 5
1
n
= 2. 1 19
9
2
3. 4.5 2.5
=
x
5.5
E. Applications Example 6. Use proportion to solve the following application. 1. The ratio of students to faculty is 25 to 2. How many faculty members will be needed for a student population of 625? 2. A worker in a factor produces 32 parts in 5 hours. At that rate, how many parts can she produces in 20 hours? ***************************************************************************************************** Read: Section 5.3/5.4